Quantifier without quantifiable token

slevithan · Oct 27, 2024 · bee04ff · bee04ff
1 parent e04c55d
commit bee04ff
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Showing 4 changed files with 11 additions and 5 deletions.
diff --git a/dist/index.min.js b/dist/index.min.js
diff --git a/src/parse.js b/src/parse.js
@@ -345,11 +345,16 @@ function parseGroupOpen(context, state) {
 
 function parseQuantifier({token, parent}) {
   const {min, max, greedy, possessive} = token;
-  if (!parent.elements.length) {
+  const quantifiedNode = parent.elements.at(-1);
+  if (
     // First child in `Alternative`
-    throw new Error('Nothing to repeat');
+    !quantifiedNode ||
+    // `\K` or `(?im-x)`
+    quantifiedNode.type === AstTypes.Directive
+  ) {
+    throw new Error(`Quantifier requires a repeatable token`);
   }
-  const node = createQuantifier(parent.elements.at(-1), min, max, greedy, possessive);
+  const node = createQuantifier(quantifiedNode, min, max, greedy, possessive);
   parent.elements.pop();
   return node;
 }

diff --git a/src/tokenize.js b/src/tokenize.js
@@ -513,6 +513,7 @@ function createTokenForFlagMod(raw, context) {
   if (raw.endsWith(')')) {
     // Replace flag x value until the end of the current group
     context.replaceCurrentModX(isXOn);
+    // Can't remove flag directives without flags like `(?-)`; they affect following quantifiers
     return createToken(TokenTypes.Directive, raw, {
       kind: TokenDirectiveKinds.flags,
       flags: flagChanges,

diff --git a/src/transform.js b/src/transform.js
@@ -175,8 +175,8 @@ const FirstPassVisitor = {
   Directive({node, parent, key, container, ast, remove, replaceWith, removeAllPrevSiblings, removeAllNextSiblings}, state) {
     const {kind, flags} = node;
     if (kind === AstDirectiveKinds.flags) {
-      // Flag directive with no flags; ex: `(?-)`, `(?--)`
       if (!flags.enable && !flags.disable) {
+        // Flag directive without flags; ex: `(?-)`, `(?--)`
         remove();
       } else {
         const flagGroup = prepContainer(createGroup({flags}), removeAllNextSiblings());